1. Technical Field
This invention generally relates to motor vehicle wheel assemblies and, more particularly, to an inboard rotational drive engagement and bearing system used in conjunction with a spindle having inboard retention.
2. Discussion
Presently most vehicle wheel assemblies used in conjunction with wheels that are driven, or selectively driven, utilize devices to retain the hub which are accessed from the outboard end of the wheel hub, and are therefore referred to as "outboard retention" devices. The hub typically provides for mounting of a wheel as well as mounting of a brake disc rotor at an outboard region. The outboard retention device is tightened to a specified range which controls the preload on bearings which support the hub relative to the steering knuckle or other non-rotating portions of the wheel assembly. A disadvantage of conventional outboard retention devices retaining the hub to the wheel assembly and establishing the preload on the bearings is that there is axial run out or end play inherent in the system. The axial run out is a result of the fact that there is an upper limit to the bearing preload which can be established and still allow the bearings to function properly. This upper limit still allows variation in the axial position of the hub and attached rotor. Axial run out is a disadvantage because of the variation in inboard/outboard position that the brake disc rotor has relative to the brake pads which are typically positioned on the inboard and outboard sides of the disc.
Further, it is presently convention within the industry to provide driving rotational torque to the hub of the wheel assembly at its outboard end. By transferring the torque to the outboard edge of the hub there is a requirement that the axle, spindle, or outer stem which transfers the torque be of significantly greater structure than if the torque were transferred at the inboard edge of the hub. Since it is beneficial to reduce the weight of the vehicle to improve fuel economy and performance, and it is particularly beneficial to reduce the unsprung weight of the vehicle suspension because of the additional benefit to handling and response, it is a significant advantage to provide rotational driving forces to the inboard edge of the hub.
The present invention overcomes several of the disadvantages indicated above, and utilizes the advantages to provide a robust vehicle wheel assembly having inboard rotational drive engagement and inboard retention.